Hydroprocessing in general refers to a process of contacting a feedstock with hydrogen at an elevated temperature and pressure using catalyst which may vary according to the types of the feedstock, the purpose and the condition of the process.
A classic example of hydroprocessing is the so called hydrotreating process, which refers to a process of contacting a petroleum feedstock with hydrogen at an elevated temperature and pressure using hydrotreating catalyst to, for example, remove or lower the sulfur contaminant from the feedstock. Hydrotreating itself can have different purposes and conditions such as but not limited to hydrogenation, hydrodesulfurization and hydrodenitrogenation, hydrodeoxygenation, and aromatics saturation.
In recent years, laboratory and commercial tests have demonstrated that vegetable oils and/or animal fats can be added to a refinery hydrotreater to produce transportation fuels. However, unlike the petroleum based feedstock, it is found that carbon monoxide and carbon dioxide can be generated in the process of hydrotreating vegetable oils and/or animal fats.
Since it is well known in the literature (Topics in Catalysis (2009) 52:229-240, Bjorn Donnis et al.) that co-feeding CO or CO2 with H2 inhibits sulfur removal, it is therefore highly desirable to 1) understand the impact of the CO and CO2 generated from the process of hydrotreating vegetable oils and/or animal fat oil on catalyst activity, and 2) improve the process and catalyst for hydroprocessing vegetable oils and/or animal fat oil including improving the activity of the hydroprocessing catalyst.